The California-based company headed by the Internet entrepreneur and billionaire is aiming to revolutionize the rocket industry by making the equipment as reusable as commercial planes, potentially saving millions of dollars.

Currently, rocket pieces fall into the ocean after launch and cannot be salvaged for another flight.

But SpaceX has a long way to go before it can hone the technology so that the first stage of the rocket can be flown back in a controlled manner and set down carefully on an ocean platform.

The company's first public attempt in January also failed, when the rocket broke into pieces after colliding with the autonomous droneship, the floating platform which is marked with an X.

SpaceX has done other practise runs, in the form of controlled landings over water, but without a droneship positioned. Landing on a hard surface requires much greater precision.

Musk had said Monday that the chances of success this time were about 50-50, but that the company believes it has an 80 percent chance of success by the end of the year since many launches lie ahead.